CN115289703A - Temperature control method - Google Patents

Abstract

The present invention relates to the technical field of heat exchange, and the present invention provides a temperature control method, comprising a second set threshold based on the operating temperature of the second circulating liquid circuit, and the second set threshold is divided into several temperature zones according to set intervals section; control the operating temperature to be at the minimum value in the current temperature section, and control the second circulating liquid circuit to load a set load, disconnect the second heat exchange passage, and obtain the refrigeration at the inlet end of the second compressor The evaporation temperature of the agent is controlled; the target value of the evaporation temperature at the outlet end of the second heat exchange passage is controlled to be less than or equal to the evaporation temperature. In the temperature control method provided by the present invention, by setting a regenerator, the cooling capacity of the no-load state is stored, the power consumption of the temperature control device is reduced, and the energy utilization rate is improved.

Description

Temperature control method

technical field

The invention relates to the technical field of heat exchange, in particular to a temperature control method.

Background technique

During the etching process in the field of semiconductor manufacturing, the radio frequency device will generate a lot of heat, and the temperature change of the wafer will affect the etching accuracy. The temperature control device continuously feeds the heat exchange medium into the processing platform to take away the generated heat in time to realize the temperature control of the wafer processing environment. In the different processing steps of the etching process, the required processing ambient temperature is quite different, and the wafer needs to wait for the heat exchange medium to adjust to the new target temperature before proceeding to the next processing step. In order to shorten the heating and cooling time of the heat exchange medium and improve the wafer processing efficiency, the latest temperature control devices adopt a dual-channel design, one channel provides low-temperature medium, and the other provides high-temperature medium. When the processing chamber needs high temperature or low temperature, select the corresponding temperature. The channel communicates with the processing chamber, and the inlet and outlet pipelines of the other channel are short-circuited. The channel connected with the processing chamber needs to take away the heat in the processing chamber in time. Its refrigeration system is in the working condition of continuously changing heat load, while the other channel has no external heat load and is in an empty-load operation state. Its refrigeration system only needs to output a small amount of cooling. Just keep the temperature of the circulating fluid constant.

In related technologies, the temperature control of the low-temperature channel of the dual-channel temperature control device can reach -70°C or lower, and a multi-stage cascade refrigeration system is generally used to achieve the cooling target temperature; the temperature of the high-temperature channel is controlled at about 10°C, and single-stage refrigeration is generally used System implementation. Due to the low energy efficiency ratio of the cascade refrigeration system, the low temperature channel has high power consumption and low energy efficiency. At the same time, in order to maintain stable temperature control during no-load conditions, the channels in the no-load state require the compressor to operate in a partially unloaded state, which also causes a waste of energy.

Contents of the invention

The invention provides a temperature control method to solve the defects of high power consumption and low energy efficiency of the refrigeration system in the prior art. According to the operating characteristics of the switching device, at any moment, the refrigeration system of one channel connected to the processing chamber is in the condition of changing heat load, while the other channel is in the state of no load. By setting the cold accumulator, only a small part of the cold capacity is needed to maintain the constant temperature control of the circulation system for the refrigeration system in the empty load state, and the excess cold capacity is in the form of subcooling the liquid in the cold accumulator to make the cold The cold energy stored in the supercooled liquid stored in the regenerator is gradually released during the operation of the refrigeration system, which improves the energy efficiency ratio of the refrigeration system circuit where the heat-absorbing channel of the regenerator is located, that is, reduces the temperature control device. power consumption. The high-temperature channel stores excess cold energy in the cold accumulator and transfers it to the low-temperature channel to improve energy utilization.

A temperature control method provided by an embodiment of the present invention is applied to a temperature control device, and the temperature control device includes:

The first temperature control channel includes a first circulating liquid circuit and a first refrigeration system exchanging heat with the first circulating liquid circuit;

The second temperature control channel includes a second circulating liquid circuit and a second refrigeration system that exchanges heat with the second circulating liquid circuit, and the second refrigeration system includes a second compressor;

A switching device, which connects the first circulating liquid circuit and the second circulating liquid circuit, and is suitable for switching the on-off of the first circulating liquid circuit and the load device, and is suitable for switching the second circulating liquid circuit and the On-off of the load device;

The cold accumulator includes a first heat exchange path and a second heat exchange path that exchanges heat with the first heat exchange path, the first heat exchange path communicates with the first refrigeration system, and the second heat exchange path communicated with the second refrigeration system, the second compressor is located at the outlet end of the second heat exchange path;

Described temperature control method comprises:

Based on the fact that the operating temperature of the second circulating fluid circuit is at a second set threshold, the second set threshold is divided into several temperature sections according to set intervals;

Controlling the operating temperature to be at the minimum value in the current temperature range, and controlling the second circulating liquid circuit to load a set load, disconnecting the second heat exchange path, and obtaining refrigerant evaporation at the inlet end of the second compressor temperature;

Controlling the target value of the evaporation temperature at the outlet end of the second heat exchange passage to be less than or equal to the evaporation temperature.

According to the temperature control method provided by the present invention, in the step of obtaining the refrigerant evaporation temperature at the inlet end of the second compressor,

The pressure value at the inlet end of the second compressor is acquired, and the evaporation temperature is the evaporation temperature of the refrigerant corresponding to the pressure value.

According to the temperature control method provided by the present invention, the set load is the rated load of the second circulating liquid circuit.

According to the temperature control method provided by the present invention, in the step of controlling the second circulating liquid circuit to load a set load,

Disconnect the second circulating fluid circuit from the switching device, and control the connection of the second circulating fluid circuit to a heater, and control the power of the heater, so as to control the second circulating fluid circuit through the heater Load the set load.

According to the temperature control method provided by the present invention, it also includes:

Obtaining a first temperature at the inlet end of the first heat exchange path and a set temperature difference between the first heat exchange path and the second heat exchange path;

determining the target value, the target value being the difference between the first temperature and the set temperature difference;

Acquiring the degree of superheat at the inlet end of the second compressor;

It is determined that the degree of superheat exceeds a first set threshold, and the target value is controlled to increase or decrease.

According to the temperature control method provided by the present invention, the step of determining that the degree of superheat exceeds the first set threshold and controlling the increase or decrease of the target value includes:

determining that the degree of superheat is greater than a first threshold, where the first threshold is an upper limit of the first set threshold;

Controlling the target value to increase to a first set value to obtain the superheat degree within a first preset time period;

It is determined that the degrees of superheat within the first preset time period are all greater than the first threshold, then cyclically execute the control to increase the target value by a first set value, and obtain the degrees of superheat within the first preset time period A step of;

until the superheat degree is less than or equal to the first threshold at least once within the first preset time period.

According to the temperature control method provided by the present invention, the step of determining that the degree of superheat exceeds the first set threshold and controlling the increase or decrease of the target value includes:

determining that the degree of superheat is less than a second threshold, where the second threshold is the lower limit of the first set threshold;

Controlling the target value to reduce a second set value to obtain the superheat degree within a second preset time period;

It is determined that the degrees of superheat within a second preset time period are all less than the second threshold value, and the step of controlling the target value to reduce a second set value is executed cyclically, and obtaining the degree of superheat within a second preset time period ;

Until the superheat degree is greater than or equal to the second threshold at least once within the second preset time period.

According to the temperature control method provided by the present invention, it also includes:

Based on the difference between the evaporation temperature and the target value, the flow rate of the refrigerant in the second heat exchange path is adjusted through a PID algorithm.

According to the temperature control method provided by the present invention, the inlet end of the second compressor is provided with a pressure sensor.

According to the temperature control method provided by the present invention, the first refrigeration system includes a multi-stage refrigeration circuit that exchanges heat sequentially, and the first heat exchange path is connected between the condenser of the refrigeration circuit at one stage and the throttling member between.

In the temperature control method provided by the present invention, the control target value Tesv is less than or equal to the upper limit value, that is, under the premise that the target value Tesv is less than or equal to the upper limit value, the target value Tesv is adjusted to improve the efficiency, cold storage capacity and circulation of the refrigeration system. The operation stability of the system is optimized, the cooling capacity in the second refrigeration system is fully utilized, the structure is simple, the cooling capacity utilization rate is high, and the power consumption of the temperature control device is reduced.

Description of drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are the present invention. For some embodiments of the invention, those skilled in the art can also obtain other drawings based on these drawings without creative effort.

Fig. 1 is a schematic structural view of a temperature control device provided by the present invention;

Fig. 2 is a schematic structural diagram of another temperature control device provided by the present invention.

Wherein, Fig. 1 illustrates that the first refrigeration system includes a two-stage refrigeration circuit, and the first heat exchanger communicates with the first-stage refrigeration circuit; Fig. 2 illustrates that the first refrigeration system includes a two-stage refrigeration circuit, and the first heat exchanger communicates with the first-stage refrigeration circuit; The secondary refrigeration circuit is connected;

Fig. 3 is one of the flow diagrams of the temperature control method provided by the present invention;

Fig. 4 is the second schematic flow chart of the temperature control method provided by the present invention

Fig. 5 is the third schematic flow chart of the temperature control method provided by the present invention

Fig. 6 is the fourth schematic flow diagram of the temperature control method provided by the present invention;

Fig. 7 is the fifth schematic flow diagram of the temperature control method provided by the present invention;

Fig. 8 is the sixth schematic flow diagram of the temperature control method provided by the present invention;

Fig. 9 is the seventh schematic flow diagram of the temperature control method provided by the present invention.

Reference signs:

1. The first compressor; 2. The first condenser; 3. The first throttle; 4. The condensing evaporator; 5. The first temperature sensor; 6. The third compressor; 7. The third throttle; 8. The first evaporator; 9. The first water tank; 10. The first circulating pump; 11. The second temperature sensor; 12. The switching device; 13. The first heat exchanger; 14. The second compressor; 15. The first Two condensers; 16, the second throttling piece; 17, the second evaporator; 18, the second water tank; 19, the second circulation pump; 20, the third temperature sensor; 21, the fourth throttling piece; 22, regulating Pressure valve; 23, the fourth temperature sensor; 24, the first pressure sensor; 25, the second pressure sensor.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention , but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

In addition, in the description of the present invention, unless otherwise specified, the meanings of "plurality", "multiple roots" and "multiple groups" are two or more.

Before describing the embodiments of the present invention, the energy efficiency ratio in the refrigeration system will be described. The definition of energy efficiency ratio of refrigeration system: (cooling) cooling capacity/electric power consumption, so the higher the energy efficiency ratio, the more energy-saving. Assuming that the energy efficiency ratio of the single-stage refrigeration cycle is 2, that is to say, the compressor power of the refrigeration system in the high-temperature channel is 1kw, and the cooling capacity of the evaporator in this refrigeration system is 2kw.

This is also applicable to the cascading single refrigeration circuit. If the cooling capacity of the first evaporator 8 is 2kw, then the power of the third compressor 6 needs to be 1kw; Add the sum of the first evaporator 8, namely 3kw, so the power of the first compressor 1 needs to be 1.5kw. Then in the low-temperature channel, the cooling capacity entering the circulating fluid is 2kw, but the total compressor power is 1.5+1=2.5kw, so the energy efficiency ratio of the cascade refrigeration system is 2/2.5=0.8, which is lower than the single-stage refrigeration system a lot.

An embodiment of the present invention, as shown in FIG. 1 and FIG. 2 , provides a temperature control device, including: a first temperature control channel, a second temperature control channel, a switching device 12 and a first heat exchanger 13 .

Wherein, the first temperature control channel and the second temperature control channel can be understood as two temperature control systems with different heat exchange temperature ranges. In this embodiment and the following embodiments, the first temperature control channel is a low temperature channel, and the second The temperature control channel is a high temperature channel as an example. The difference between the low temperature channel and the high temperature channel here is that the lowest temperature range that the low temperature channel can reach is lower than the minimum temperature range that the high temperature channel can reach. For example, the low temperature channel can reach The lowest temperature can be -70°C, the lowest temperature that can be reached by the high temperature channel can be -10°C, and the highest temperature that can be reached by the high temperature channel can be 90°C.

The first temperature control channel includes the first circulating liquid circuit and the first refrigeration system that exchanges heat with the first circulating liquid circuit, and the second temperature control channel includes the second circulating liquid circuit and the second refrigeration system that exchanges heat with the second circulating liquid circuit System; the switching device 12 is connected to the first circulating liquid circuit and the second circulating liquid circuit, the switching device 12 is suitable for switching the on-off of the first circulating liquid circuit and the load device, and the switching device 12 is suitable for switching the second circulating liquid circuit and the load device on and off.

The first temperature control channel and the second temperature control channel cooperate with the switching device 12. When the load equipment needs to supply low-temperature circulating fluid, the switching device 12 controls the first circulating fluid circuit to communicate with the load device to form a circulation loop. At this time, the load device Control the short circuit of the second circulating fluid circuit (the second circulating fluid circuit forms a circulating loop); similarly, when the load equipment needs to supply high-temperature circulating fluid, the switching device 12 controls the second circulating fluid circuit to communicate with the load device and form a circulating loop, At this time, the load device controls the first circulating liquid circuit to be short-circuited (the first circulating liquid circuit forms a circulating circuit). That is, at any moment, there is only one circulating fluid circuit connected to the load device, and there will be a change in thermal load, and the other channel must be in an empty state.

In some cases, the first temperature control channel includes a first circulating liquid circuit and a first refrigeration system exchanging heat with the first circulating liquid circuit, and the first refrigeration system includes a multi-stage refrigeration circuit sequentially exchanging heat. The first refrigeration system provides cooling capacity for the first circulating liquid circuit to cool the circulating liquid. The first refrigeration system includes a multi-stage refrigeration circuit. The multi-stage refrigeration circuits exchange heat in sequence and use different refrigerants in combination to reduce evaporation step by step. Temperature, that is, the lowest temperature that can be achieved by lowering the first refrigeration system step by step, so that the evaporation temperature provided by the refrigerant in the last-stage refrigeration circuit can meet the heat exchange demand of the circulating liquid in the first circulating liquid circuit. By means of step-by-step heat exchange to meet the cooling demand, the temperature that can be achieved is lower, and the cooling temperature zone is widened, so that the temperature that can be achieved by the first temperature control channel is lower.

The first refrigeration system uses a cascade system, based on the fact that the cooling capacity in the cascade system decreases step by step, and the cooling capacity of the upper level = the cooling capacity of the lower level + the calorific value of the compressor of the lower level. Therefore, as the number of cascade systems increases, the energy efficiency ratio of the system will decrease. The main application of the cascade system is to use different types of refrigerants to achieve lower temperature requirements when a single refrigerant cannot meet the requirements.

The main reason for using the cascade system for the first temperature control channel is that in practical applications, the set temperature of the circulating fluid in the first circulating fluid circuit is low, which cannot be achieved with a single refrigerant, and only a multi-stage cascade system can be used. The basis for using several levels is the temperature. Generally, if it is -40°C to -80°C, two-level cascades are used. If it is lower than -80°C, three-level cascades are used, and four-level cascades may also be used.

In the temperature control device of this embodiment, the multi-stage refrigeration circuit is set in the first refrigeration system, which can reduce the capacity of the compressor in the first refrigeration system, reduce the overall power consumption of the temperature control device, and further reduce the cost of the temperature control device.

Of course, the first refrigeration system includes a multi-stage refrigeration circuit, and the first heat exchanger 13 includes a first heat exchange path and a second heat exchange path that exchange heat with each other, and the first heat exchange path is connected to one stage of the first refrigeration system. The refrigeration circuit is in communication, and the second heat exchange path is in communication with the second refrigeration system.

The first refrigeration system communicates with the second refrigeration system through the first heat exchanger 13, and the first heat exchanger 13 can divide a part of the refrigerant in the second refrigeration system. When the system adopts a fixed-frequency compressor, the air output of the compressor is fixed, and when the demand for heat exchange of the second evaporator 17 is not high, that is, the refrigerant flow rate in the second evaporator 17 is small, and the excess refrigerant flow rate passes through the second evaporator 17. The refrigerant in the refrigeration system absorbs heat in the second heat exchange path of the first heat exchanger 13 , which can also increase the suction pressure of the second compressor 14 and reduce the power consumption of the second compressor 14 .

Of course, when the first refrigeration system is provided with a single-stage refrigeration circuit, the first heat exchanger 13 can still be provided, that is, the first heat exchange path of the first heat exchanger 13 communicates with the refrigeration circuit of the first refrigeration system, and the second The heat exchange path communicates with the second refrigeration system.

In some embodiments, as shown in FIG. 1 and FIG. 2 , the first heat exchanger 13 is a cold storage device, the first heat exchange path is a cold storage path, and the second heat exchange path is a heat absorption path. The refrigerant in the refrigerating circuit connected to it is supercooled by the cold accumulator, and the refrigerating capacity of the refrigerating circuit can be improved after supercooling, thereby increasing the refrigerating capacity of the first refrigeration system.

When the first refrigeration system is equipped with multi-stage refrigeration circuits, each stage of refrigeration circuits can exchange heat with the second refrigeration system through the first heat exchanger (not shown in the figure), that is, multiple first heat exchangers are provided, The second refrigeration system communicates with the second heat exchange passages of the plurality of first heat exchangers, and each stage of refrigeration circuits in the first refrigeration system communicates with the first heat exchange passages of one first heat exchanger.

Referring to FIG. 1 and FIG. 2 , the first refrigeration system includes a two-stage refrigeration circuit as an example for illustration, and the two-stage refrigeration circuits may be referred to as a first-stage refrigeration circuit and a second-stage refrigeration circuit. The first-stage refrigeration circuit includes the first condenser 2 connected to form a circulation circuit, the first throttling member 3, the condensation evaporator 4 and the first compressor 1, and the second-stage refrigeration circuit includes a third compressor connected to form a circulation circuit 6. Condensing evaporator 4 , third throttling element 7 and first evaporator 8 . The first-stage refrigeration circuit can be understood as a high-temperature refrigeration circuit, and the second-stage refrigeration circuit can be understood as a low-temperature refrigeration circuit.

The first-stage refrigeration circuit and the second-stage refrigeration circuit are suitable for heat exchange, the second-stage refrigeration circuit and the first circulating liquid circuit are suitable for heat exchange, and the first heat exchange path is connected to the first-stage refrigeration circuit or the second-stage refrigeration circuit. connected, the first heat exchanger 13 can be flexibly set.

As shown in Figure 1, the first heat exchange path of the first heat exchanger 13 is connected between the first condenser 2 and the first throttling member 3, and the first heat exchange path is connected to the first-stage refrigeration circuit (which can be understood as The refrigerant in the high-temperature stage refrigeration circuit) is supercooled, and the refrigeration capacity of the high-temperature stage refrigeration circuit is improved after the refrigerant is supercooled, thereby increasing the total refrigeration capacity of the first refrigeration system.

As shown in Figure 2, the first heat exchange path of the first heat exchanger 13 is connected between the condensation evaporator 4 and the third throttling member 7, and the first heat exchange path is connected to the second-stage refrigeration circuit (which can be understood as a low temperature The refrigerant in the first-stage refrigeration circuit) performs liquid supercooling, which improves the refrigeration capacity of the low-temperature refrigeration circuit, thereby increasing the total refrigeration capacity of the first refrigeration system.

As shown in Figure 1 and Figure 2, the first heat exchanger 13 is a tank heat exchanger, the tank heat exchanger includes a shell and heat exchange tubes arranged in the shell, the first heat exchange path is the shell and the heat exchanger. The space between the heat pipes, the second heat exchange path is the space inside the heat exchange tubes. The tank heat exchanger has a simple structure and good cold storage effect.

The excess refrigeration capacity in the second refrigeration system, through the tank heat exchanger, additionally supercools the refrigerant liquid in the first refrigeration system in the tank. After the liquid is supercooled, the refrigeration capacity of this refrigeration circuit is improved, that is, the The total cooling capacity of the first cooling system.

In some embodiments, the heat exchange tube is a spiral coil, and the heat exchange area of the spiral coil is larger and the heat exchange effect is better.

In some embodiments, as shown in FIG. 1 and FIG. 2, the second refrigeration system includes a second compressor 14, a second condenser 15, a second throttling element 16, and a second evaporator 17 connected as a circulation loop, A fourth throttling member 21 is disposed between the outlet end of the second condenser 15 and the inlet end of the second heat exchange passage, and the outlet end of the second heat exchange passage is located at the inlet end of the second compressor 14 . The second heat exchange path plays the role of evaporating and absorbing heat in the second refrigeration system, and then supercools the refrigerant in the first refrigeration system.

In some embodiments, as shown in FIG. 2 , the outlet end of the second evaporator 17 is provided with a pressure regulating valve 22 . By setting the pressure regulating valve 22, the pressure at the outlet end of the second evaporator 17 is kept stable.

As shown in FIG. 1 , the outlet end of the second evaporator 17 is not provided with a pressure regulating valve 22. During the operation of the temperature control device, the vapor pressure at the outlet end of the second evaporator 17 is different from that at the outlet end of the second heat exchange passage. If the vapor pressure is within the preset range, that is, the lowest temperature that the condensing evaporator 4 and the second evaporator 17 can reach is within the preset temperature range, then the vapor pressure at the outlet of the second evaporator 17 may not be adjusted.

It should be noted that a pressure regulating valve 22 may also be provided at the outlet end of the second evaporator 17 shown in FIG. 1 . After the operating condition of the first-stage refrigeration circuit shown in FIG. 1 is adjusted, the pressure regulating valve 22 can ensure the stable operation of the second compressor 14 .

In some embodiments, as shown in FIG. 1 , the first heat exchange path communicates with the first-stage refrigeration circuit, and a second pressure sensor 25 is provided between the second compressor 14 and the second evaporator 17 of the second refrigeration system. . The second pressure sensor 25 is used to detect the pressure at the inlet end of the second compressor 14 .

According to the difference between the measured value of the second pressure sensor 25 and the target value, a PID (proportional-integral-derivative) algorithm is invoked to adjust the opening of the fourth throttling member 21 to control the heat exchange rate in the first heat exchanger 13 .

In some embodiments, as shown in FIG. 2 , the first heat exchange path communicates with the second-stage refrigeration circuit, and a first pressure sensor 24 is provided at the outlet end of the second heat exchange path. The first pressure sensor 24 is used to detect the pressure at the inlet end of the second compressor 14 .

According to the difference between the measured value of the first pressure sensor 24 and the target value, a PID (proportional-integral-derivative) algorithm is invoked to adjust the opening degree of the fourth throttling member 21 to control the heat exchange rate in the first heat exchanger 13 .

As shown in FIG. 2 , the first pressure sensor 24 cooperates with the pressure regulating valve 22 so that the steam pressure at the inlet end of the second compressor 14 meets the requirements of the working conditions.

In some embodiments, the first heat exchange passage is located before the inlet of the throttling member of the refrigeration circuit. Referring to Fig. 1 and Fig. 2, the first heat exchange path is connected in series with the first condenser 2, and the refrigerant is subcooled through two-stage heat exchange.

In some embodiments, as shown in FIG. 2 , a first temperature sensor 5 is provided at the inlet end of the first heat exchange path to detect the temperature of the refrigerant flowing into the first heat exchange path, that is, to detect the temperature of the refrigerant before it is supercooled. According to the temperature, the cooling capacity supplied by the second heat exchange path is adjusted to ensure the supercooling effect.

Referring to FIG. 1 and FIG. 2 , the inlet end of the second compressor 14 is provided with a fourth temperature sensor 23 .

Referring to Fig. 1 and Fig. 2, the first circulating liquid circuit comprises a first water tank 9, a first circulating pump 10 and a second temperature sensor 11, and the circulating liquid in the first water tank 9 flows to Switching device 12, the circulating fluid in the first water tank 9 is suitable for flowing into the first evaporator 8 and exchanging heat with the refrigerant in the first evaporator 8, and the first circulating pump 10 can be arranged upstream of the first evaporator 8 or downstream, which can be selected according to needs, the second temperature sensor 11 is arranged at the inlet end of the switching device 12 .

Of course, the first circulating liquid circuit can also be provided with a first heater, and the first heater is arranged between the outlet port of the first evaporator 8 and the inlet port of the switching device 12, so as to control the circulating liquid in the first circulating liquid circuit. The temperature can be precisely adjusted.

The second circulating liquid loop comprises a second water tank 18, a second circulating pump 19 and a third temperature sensor 20, and the circulating liquid in the second water tank 18 flows to the switching device 12 under the action of the second circulating pump 19, and in the second water tank 18 The circulating liquid is suitable for flowing into the second evaporator 17 and exchanging heat with the refrigerant in the second evaporator 17. The second circulating pump 19 can be arranged upstream or downstream of the second evaporator 17, which can be selected according to needs. The third temperature sensor 20 is arranged at the inlet end of the switching device 12 .

Of course, the second circulating liquid circuit can also be provided with a second heater, and the second heater is arranged between the outlet port of the second evaporator 17 and the inlet port of the switching device 12, so as to control the circulating liquid in the second circulating liquid circuit. The temperature can be precisely adjusted.

The aforementioned first throttling element 3 , second throttling element 16 and third throttling element 7 can be selected from thermal expansion valves or electronic expansion valves.

Based on the above-mentioned temperature control device, in combination with those shown in Figures 1 to 4, a temperature control method is provided, including:

Step 110, obtaining the first temperature of the inlet end of the first heat exchange passage and the set temperature difference between the first heat exchange passage and the second heat exchange passage;

Referring to Figure 2, the first temperature may be T1 measured by the first temperature sensor 5, and the set temperature difference between the first heat exchange path and the second heat exchange path may be a value set in the system, such as 10°C , 15°C, 20°C. There is a temperature difference between the first heat exchange path and the second heat exchange path, so that heat exchange is performed between the first heat exchange path and the second heat exchange path.

Step 120, determining the target value Tesv of the evaporation temperature at the outlet end of the second heat exchange passage, wherein the target value Tesv is the difference between the first temperature and the set temperature;

The target value Tesv is determined according to the first temperature T1 to ensure the heat exchange temperature difference between the first heat exchange path and the second heat exchange path, ensure the heat exchange efficiency between the first heat exchange path and the second heat exchange path, and improve the first heat exchange path. Cooling capacity of the heat exchanger.

Step 130, obtaining the degree of superheat SH at the inlet end of the second compressor, which is located at the outlet end of the second heat exchange path;

The refrigerant in the second heat exchange path flows to the second compressor, and the refrigerant in the second heat exchange path will affect the degree of superheat at the inlet end of the second compressor.

Among them, the degree of superheat SH refers to the superheated steam temperature minus the saturation temperature under the corresponding pressure.

The measured value of the first pressure sensor 24 or the second pressure sensor 25 is collected, the measured value corresponds to the pressure, and the evaporation temperature corresponding to the pressure is calculated according to the characteristics of the refrigerant type of the second refrigeration system. The measured value of the fourth temperature sensor 23 is collected, and this measured value is the superheated steam temperature. Based on the two measured values, the degree of superheat SH can be calculated.

Step 140, it is determined that the superheat SH exceeds the first set threshold, and the control target value Tesv increases or decreases.

The first set threshold is a numerical range, such as 8 ° C ~ 15 ° C, the degree of superheat SH exceeding the first set threshold is divided into the upper limit (15 ° C) of the degree of superheat greater than the first set threshold, and the degree of superheat SH is less than the first set threshold. Set the lower limit of the threshold (8°C). When the degree of superheat SH is greater than the upper limit of the first set threshold, the control target value Tesv increases, so that the temperature difference between the first heat exchange passage and the second heat exchange passage increases, and the temperature difference between the first heat exchange passage and the second heat exchange passage increases. The heat exchange efficiency between the heat paths; when the degree of superheat SH is less than the lower limit of the first set threshold, the control target value Tesv decreases.

Taking the structure shown in Figure 1 and Figure 2 as an example, under the condition that the amount of heat exchange between the second heat exchange passage and the first heat exchange passage is constant, when the refrigerant flow rate in the second heat exchange passage is small, the second compressor The degree of superheat SH at the inlet end is relatively large, and when the refrigerant flow rate in the second heat exchange passage is relatively large, the degree of superheat SH at the inlet end of the second compressor is relatively small.

Based on the degree of superheat SH can be used to characterize whether the heat transfer of the refrigerant is sufficient. Adjusting the evaporation temperature target value Tesv at the inlet end of the second compressor through the degree of superheat SH can ensure heat exchange efficiency and cold storage capacity.

The above process is illustrated by an example: assuming that the target evaporation temperature Tesv of the second heat exchange channel is -20°C at this moment, when the load of the first refrigeration system is high, the liquid in the first heat exchange channel can be cooled to -10°C. When the load of the first refrigeration system is reduced, the liquid in the first heat exchange channel is cooled to -15°C. Since the temperature difference between the two sides of the first heat exchanger is too small, heat exchange cannot continue, and the excess cooling capacity in the second refrigeration system cannot Continue to store in the first heat exchange channel. At this time, it is necessary to reduce the target value of evaporation temperature Tesv. Assuming that the target value Tesv is reduced to -25°C, the heat exchange temperature difference between the first heat exchange channel and the second heat exchange channel will increase, and the liquid in the first heat exchange channel can be continuously reduced to -20°C, that is, the cold storage capacity has been increased.

However, since the efficiency of the second refrigeration system decreases with the decrease of the evaporation temperature target value Tesv, the cold storage rate will decrease. Therefore, when the load demand of the first refrigeration system increases, the evaporation temperature target value Tesv needs to be increased to increase the cold storage rate.

On the basis of the above-mentioned temperature control method, that is, in step 140, that is, in the step of determining that the degree of superheat SH exceeds the first set threshold, the step of controlling the target value Tesv to increase or decrease includes:

Step 141, determining that the degree of superheat SH is greater than a first threshold, and the first threshold is the upper limit of the first set threshold;

For example, the first threshold is 15° C., but not limited to 15° C., which can be set according to actual needs.

Step 142, control the target value Tesv to increase the first set value, and obtain the degree of superheat SH within the first preset time period;

The first set value can be 1° C., 2° C., etc., which can be set as required.

The first preset duration can be 10 seconds, 20 seconds, 30 seconds, etc., which can be specifically set according to needs.

The purpose of increasing the control target value Tesv by the first set value is to reduce the degree of superheat SH.

Step 143, determining that the degree of superheat SH is greater than the first threshold value, then cyclically execute the step of increasing the control target value Tesv by the first set value, and obtaining the degree of superheat SH within the first preset time length;

The control target value Tesv is increased by the first set value once, and all the superheat degrees SH obtained within the first preset time period are greater than the first threshold value, then the control target value Tesv is increased by the first set value again, and the first set value is confirmed again. The obtained superheat degree SH within a preset time length is all greater than the first threshold value, then loop the aforementioned "control target value Tesv to increase the first set value, and obtain the superheat degree within the first preset time length", so that the superheat The heat SH falls within the range of the first set threshold.

Step 144, until the superheat SH within the first preset time period is less than or equal to the first threshold.

In the step of "increase the control target value Tesv by the first set value, and obtain the degree of superheat within the first preset time period", if at least one degree of superheat SH within the first preset time period is less than or equal to the first threshold, then The above-mentioned cycle is stopped, that is, the target value Tesv does not need to be increased, and the adjustment of the target value Tesv is completed once.

It should be noted that if at least one degree of superheat SH within the first preset time period is less than or equal to the first threshold, it can indicate that the degree of superheat SH is floating around the first threshold, that is, the degree of superheat SH is close to the first set threshold, which is not strictly The specific numerical value of degree of superheat SH is limited.

In an embodiment different from the aforementioned steps 141 to 144, in step 140, that is, in the step of determining that the degree of superheat SH exceeds the first set threshold and increasing or decreasing the control target value Tesv, it also includes:

Step 145, determining that the degree of superheat SH is less than a second threshold, and the second threshold is the lower limit of the first set threshold;

For example, the first threshold is 8° C., but not limited to 8° C., which can be set according to actual needs.

Step 146, the control target value Tesv is lowered by a second set value, and the superheat degree SH within the second preset time period is acquired;

The second set value can be the same as or different from the first set value, for example, the second set value is 1°C or 2°C, which can be selected according to needs.

The second preset duration can be the same as or different from the first preset duration, such as 10 seconds, 20 seconds or 30 seconds, which can be specifically selected according to needs.

Step 147, determine that the degree of superheat SH is less than the second threshold value, execute the step of reducing the control target value Tesv by the second set value in a loop, and obtain the degree of superheat SH within the second preset time length,

The control target value Tesv is lowered by the second set value once, and the obtained superheat SH within the second preset time period is all less than the second threshold value, then the control target value Tesv is lowered by the second set value again, and the second preset value is confirmed again. Assuming that all the superheat degrees SH obtained within the time period are less than the second threshold value, then loop the above-mentioned "control target value Tesv to reduce the second set value, and obtain the superheat degree within the second preset time period", so that the superheat degree SH increases. High to within the range of the first set threshold.

Step 148, until the superheat SH within the second preset time period is greater than or equal to the second threshold.

In the step of "reducing the control target value Tesv to the second set value, and obtaining the degree of superheat within the second preset time period", if at least one degree of superheat SH within the second preset time period is greater than or equal to the second threshold, stop The above-mentioned cycle, that is, the target value Tesv does not need to be lowered, and one adjustment of the target value Tesv is completed.

It should be noted that if at least one degree of superheat SH within the second preset time period is greater than or equal to the second threshold, it can indicate that the degree of superheat SH is floating around the second threshold, that is, the degree of superheat SH is close to the first set threshold, which is not strictly The specific numerical value of degree of superheat SH is limited.

It should be noted that steps 141 to 144 and steps 145 to 148 are parallel solutions, and one of them is selected and executed according to the actual situation, and is not executed in the order of step numbers. Wherein, the embodiment of the temperature control method, as shown in FIG. 4 , includes: according to the temperature value T1 of the inlet end of the first heat exchange path, the target value of evaporation temperature Tesv at the outlet end of the second heat exchange path is calculated, and according to the second The superheat degree SH at the inlet end of the compressor 14 is adjusted to a target value Tesv.

Among them, the measured value of the first temperature sensor 5 is collected as T1, the set temperature difference between the first heat exchange path and the second heat exchange path is 15°C, and the target value of the evaporation temperature at the outlet end of the second heat exchange path is calculated as Tesv=T1- 15.

Set the appropriate range of superheat SH, for example, set the first set threshold to 8-15°C, when the superheat SH>15°C, the first preset duration is 30 seconds, every 30 seconds, set the target value Increase the Tesv value by 1°C until at least one of the superheat SH obtained within 30 seconds is not higher than 15°C and stop adjusting; when the superheat SH<8°C, the second preset duration is 30 seconds, every 30 seconds Time, reduce the target value Tesv value by 1°C, and stop the adjustment until at least one of the superheat degrees SH obtained within 30 seconds is not lower than 8°C.

As shown in Figure 5, the temperature control method also includes:

Step 210, based on the operating temperature of the second circulation system, determine the upper limit of the target value Tesv;

Step 220, the control target value Tesv is less than or equal to the upper limit value.

Based on the operating temperature of the second circulation system, an upper limit of the target value is determined, and the target value is controlled to be less than or equal to the upper limit.

The operating temperature of the second circulation system may be a temperature range, for example, the operating temperature of the second circulation system is 10°C-90°C, and the current temperature range is 20°C-30°C.

During the operation of the second circulation system in the current temperature range, the pressure value at the inlet end of the second compressor corresponds to the evaporation temperature Teh of the refrigerant, and the evaporation temperature can be used as the upper limit of the target value Tesv, and the target value Tesv is controlled to be less than equal to this upper limit.

In other temperature control methods for adjusting the target value Tesv, it can be ensured that the target value Tesv is less than or equal to the upper limit value, that is, on the premise that the target value Tesv is less than or equal to the upper limit value, the target value Tesv is adjusted by other methods to achieve To optimize the efficiency of the refrigeration system, the cold storage capacity and the operation stability of the circulation system.

This temperature control method can be applied in a temperature control device without a pressure regulating valve.

On the basis of the above-mentioned embodiments, as shown in FIG. 6, in step 210, that is, in the step of determining the upper limit of the target value based on the operating temperature of the second circulation system,

Step 410, based on the fact that the temperature range of the second circulating fluid circuit is within a second set threshold, the second set threshold is divided into several temperature sections according to set intervals;

For example, the second set threshold value is 10°C-90°C, the set interval is 10°C, and every 10°C is divided into a section, a total of 8 sections, and the current temperature section is 20°C-30°C.

Step 420, controlling the operating temperature to be at the minimum value in the current temperature range, disconnecting the second heat exchange path, and obtaining the evaporation temperature Teh of the refrigerant at the inlet end of the second compressor;

Step 430, determining the evaporation temperature Teh as the upper limit of the target value.

Wherein, the evaporation temperature of the refrigerant at the inlet end of the second compressor can be obtained by obtaining the pressure value at the inlet end of the second compressor, and based on the pressure value and the type of refrigerant, the evaporation temperature of the refrigerant under this pressure value can be obtained temperature. Of course, the evaporation temperature of the refrigerant can also be obtained by other methods.

Control the operating temperature of the second circulation system at the minimum value between 20°C and 30°C, that is, the operating temperature is at 20°C, and control the second heat exchange path to be disconnected to stop cold storage. At this time, the inlet of the second compressor is obtained end pressure value, and according to this pressure value, the refrigerant evaporation temperature Teh corresponding to this pressure value is obtained, and this evaporation temperature Teh is used as the upper limit value of the target value Tesv. As shown in Figure 7, it is suitable for the system shown in Figure 1, that is, the system without the pressure regulating valve 22, including: according to the operating temperature of the second circulating fluid circuit, setting the target value of the evaporation temperature at the outlet end of the second heat exchange passage Upper limit of Tesv.

Among them, the operating range of the outlet temperature of the second circulating fluid circuit is divided into several sections, and each section operates at the lowest temperature, and the fourth throttling member 21 is closed, so that the second circulating fluid circuit can run stably at the maximum rated load amount, record the measured value of the second pressure sensor 25 at this time, and convert the evaporation temperature Teh of the refrigerant obtained according to the measured value of the second pressure sensor 25 and the type of refrigerant, which is the corresponding second temperature in this temperature range. The upper limit of the target evaporation temperature Tesv at the outlet end of the heat exchange channel. In the adjustment of the target value Tesv by other temperature control methods, it is necessary to ensure that the target value Tesv<=the evaporation temperature Teh of the refrigerant.

The above method is illustrated by an example: the temperature range of the second circulating liquid circuit is set to be 10° C. to 90° C., and every 5° C. is divided into a section, a total of 16 sections. For the temperature section of 20°C-25°C, the minimum temperature of this temperature section is 20°C, and the fourth throttling member 21 is closed to make the second circulating fluid circuit load the rated load and run stably, then measure the second pressure sensor 25 The measured pressure value is 0.5MPa, assuming that the refrigerant in the second refrigeration system is R404A, then under the pressure of 0.5MPa, the evaporation temperature of R404A is -6°C. At this time, the upper limit value of the target evaporation temperature Tesv at the outlet end of the second heat exchange channel is -6°C. After calculating Tesv based on the first temperature T1 measured by the first temperature sensor 5 and the degree of superheat SH, as Above -6°C, Tesv is constant at -6°C.

Among them, in step 420, it is carried out during the production and debugging process of the machine, and the second circulation loop can be controlled to run under the set load. At this time, the second circulation loop needs to be connected to a heater instead of a switching device. , use the heater to output a certain power, this power can be adjusted according to needs, the heat load corresponding to this power is the set load, in some cases, the set load can be the rated load designed by the second circulation system.

As shown in Figure 8 and Figure 9, the temperature control method also includes:

Step 310, obtaining the pressure value at the inlet end of the second compressor;

The pressure value can be measured by the second pressure sensor 25 shown in FIG. 1 , or by the second pressure sensor 24 shown in FIG. 2 .

Step 320, based on the pressure value and the type of refrigerant at the inlet end of the second compressor, determine the evaporation temperature Tepv of the refrigerant;

For example, when the pressure value measured by the second pressure sensor 25 is 0.5 MPa, the evaporation temperature Tepv of the refrigerant R404A is -6°C, and -6°C is the evaporation temperature Tepv.

Step 330, based on the difference between the evaporation temperature Tepv and the target value Tesv, adjust the flow rate of the refrigerant in the second heat exchange path through the PID algorithm.

The flow rate of the refrigerant in the second heat exchange path, that is, the opening degree of the fourth throttling member 21 is controlled by a PID algorithm, so that the target value Tesv is close to the evaporation temperature Tepv.

Wherein, in this embodiment, the evaporation temperature Tepv is obtained in the same way as the evaporation temperature The in the above embodiment, the difference is that in this embodiment, no specific operating conditions are limited.

An embodiment of the temperature control method, as shown in FIG. 9 , includes: according to the difference between the evaporation temperature target value Tesv at the outlet end of the second heat exchange passage and the evaporation temperature Tepv at the inlet end of the second compressor 14, wherein the second compression The evaporation temperature Tepv at the inlet end of the machine 14 is the evaporation temperature corresponding to the pressure value measured by the second pressure sensor 25, and the PID algorithm is called to control the opening of the second heat exchange passage (the fourth throttling part 21), thereby controlling the first The amount of heat exchange in the heat exchanger 13.

Wherein, the value method of the evaporation temperature target value Tesv can adopt the above-mentioned temperature control method.

Taking the temperature control device for regulating the temperature of the heating chamber as an example, the circulation pump is used to pump the circulating liquid into the switching device 12, one of which circulates into the processing chamber of the etching equipment to absorb the heat during the etching process, making the processing chamber The temperature is constant, and the circulating fluid returns to the original circulation channel through the switching device 12; the other circulating fluid directly returns to the original circulating system in the switching device 12.

When the circulating fluid in the first circulating fluid circuit (low temperature) enters the processing chamber for temperature control, the second circulating fluid circuit (high temperature) operates without heat load or with low heat load. Under the premise that the heat transfer in the evaporator 17 of the second circulating liquid circuit (high temperature) meets the demand, the fourth throttling member 21 in the second refrigeration system can be opened to make the second heat exchange of the first heat exchanger 13 The channel exchanges heat with the first heat exchange channel to realize supercooling of the liquid refrigerant in a certain refrigeration circuit in the first refrigeration system. On the one hand, the excess cold capacity of the second refrigeration system is transferred to the first refrigeration system. The liquid refrigerant in the first heat exchange channel located in the first heat exchanger 13 is used as a cold storage medium to store the excess cold capacity of the second refrigeration system; on the other hand, the supercooled refrigerant liquid improves the Cooling capacity output of a refrigeration system to meet high load demands.

Because the load of the first refrigeration system fluctuates according to different working conditions, when the load of the first refrigeration system is not high, the consumption of cold storage in the first heat exchanger 13 decreases. In order to ensure that the second refrigeration system can continuously store the excess cooling capacity in the first heat exchanger 13, the evaporation temperature in the second heat exchange channel needs to be reduced, that is, the liquid temperature in the first heat exchange channel can be cooled to a lower temperature , the cold storage process can continue.

Based on the above temperature control device, another temperature control method is provided, including:

According to the measured value PV1 of the first outlet temperature of the first circulating fluid circuit and the set value SV1 of the first outlet temperature of the first circulating fluid circuit, the first temperature difference ΔT1 is obtained, and the first temperature difference ΔT1 is adjusted according to the first temperature difference ΔT1 In a refrigeration system, the openings of the throttling parts (the first throttling part 3 and the third throttling part 7 in Fig. 1 and Fig. 2) in the refrigeration circuits at all levels in the refrigeration system are adjusted to adjust the evaporators in the refrigeration circuits at all levels (as shown in Fig. 1 and the heat exchange of the condensing evaporator 4 and the first evaporator 8) in FIG. 2, thereby realizing the precise control of the outlet temperature of the first temperature control channel.

Among them, ΔT1=SV1-PV1. The opening degree of each throttling piece is adjusted according to the PID algorithm.

Another temperature control method includes: obtaining the second temperature difference ΔT2 according to the measured value PV2 of the second outlet temperature of the second circulating fluid circuit and the set value SV2 of the second outlet temperature of the second circulating fluid circuit, according to The second temperature difference ΔT2 adjusts the opening degree of the second throttling member 16 in the second refrigerating system, and adjusts the heat transfer capacity of the second evaporator 17, thereby realizing precise control of the outlet temperature of the second temperature control channel.

Among them, ΔT2=SV2-PV2. The opening degree of the second throttling member 16 is adjusted according to the PID algorithm.

Another temperature control method includes: obtaining the preset temperature of the degree of superheat and the actual degree of superheat, the actual degree of superheat is the degree of superheat of the refrigerant between the outlet end of the evaporator and the inlet end of the compressor in each refrigeration circuit, according to The deviation of the actual superheat from the preset temperature adjusts the opening of the throttle.

Wherein, the preset temperature may be a point value or a value range.

As shown in Figures 1 and 2, in the first-stage refrigeration circuit, between the outlet end of the condensing evaporator 4 and the inlet end of the first compressor 1, the temperature is adjusted according to the deviation between the first actual degree of superheat and the first preset temperature. The opening degree of the first throttling member 3.

In the second-stage refrigeration circuit, between the outlet end of the first evaporator 8 and the inlet end of the third compressor 6, the opening of the third throttling member 7 is adjusted according to the deviation between the second actual degree of superheat and the second preset temperature. Spend.

In the second refrigeration system, between the outlet port of the second evaporator 17 and the inlet port of the second compressor 14, the opening degree of the second throttling member 16 is adjusted according to the deviation between the third actual degree of superheat and the third preset temperature .

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. a temperature control method, is characterized in that, is applied to temperature control device, and described temperature control device comprises: The first temperature control channel includes a first circulating liquid circuit and a first refrigeration system exchanging heat with the first circulating liquid circuit; The second temperature control channel includes a second circulating liquid circuit and a second refrigeration system that exchanges heat with the second circulating liquid circuit, and the second refrigeration system includes a second compressor; A switching device, which connects the first circulating liquid circuit and the second circulating liquid circuit, and is suitable for switching the on-off of the first circulating liquid circuit and the load device, and is suitable for switching the second circulating liquid circuit and the On-off of the load device; The cold accumulator includes a first heat exchange path and a second heat exchange path that exchanges heat with the first heat exchange path, the first heat exchange path communicates with the first refrigeration system, and the second heat exchange path communicated with the second refrigeration system, the second compressor is located at the outlet end of the second heat exchange path; Described temperature control method comprises: Based on the fact that the operating temperature of the second circulating fluid circuit is at a second set threshold, the second set threshold is divided into several temperature sections according to set intervals; Controlling the operating temperature to be at the minimum value in the current temperature range, and controlling the second circulating liquid circuit to load a set load, disconnecting the second heat exchange path, and obtaining refrigerant evaporation at the inlet end of the second compressor temperature; Controlling the target value of the evaporation temperature at the outlet end of the second heat exchange passage to be less than or equal to the evaporation temperature. 2. The temperature control method according to claim 1, characterized in that, in the step of obtaining the refrigerant evaporation temperature at the inlet end of the second compressor, The pressure value at the inlet end of the second compressor is acquired, and the evaporation temperature is the evaporation temperature of the refrigerant corresponding to the pressure value. 3 . The temperature control method according to claim 1 , wherein the set load is the rated load of the second circulating liquid circuit. 4 . 4. The temperature control method according to claim 1, characterized in that, in the step of controlling the second circulating liquid circuit to load a set load, Disconnect the second circulating fluid circuit from the switching device, and control the connection of the second circulating fluid circuit to a heater, and control the power of the heater, so as to control the second circulating fluid circuit through the heater Load the set load. 5. The temperature control method according to claim 1, further comprising: Obtaining a first temperature at the inlet end of the first heat exchange path and a set temperature difference between the first heat exchange path and the second heat exchange path; determining the target value, the target value being the difference between the first temperature and the set temperature difference; Acquiring the degree of superheat at the inlet end of the second compressor; It is determined that the degree of superheat exceeds a first set threshold, and the target value is controlled to increase or decrease. 6. The temperature control method according to claim 5, wherein the step of determining that the degree of superheat exceeds a first set threshold and controlling the increase or decrease of the target value comprises: determining that the degree of superheat is greater than a first threshold, where the first threshold is an upper limit of the first set threshold; Controlling the target value to increase to a first set value to obtain the superheat degree within a first preset time period; It is determined that the degrees of superheat within the first preset time period are all greater than the first threshold, then cyclically execute the control to increase the target value by a first set value, and obtain the degrees of superheat within the first preset time period A step of; Until the superheat degree is less than or equal to the first threshold at least once within the first preset time period. 7. The temperature control method according to claim 5, wherein the step of determining that the degree of superheat exceeds a first set threshold and controlling the increase or decrease of the target value comprises: determining that the degree of superheat is less than a second threshold, where the second threshold is the lower limit of the first set threshold; Controlling the target value to reduce a second set value to obtain the superheat degree within a second preset time period; It is determined that the degrees of superheat within a second preset time period are all less than the second threshold value, and the step of controlling the target value to reduce a second set value is executed cyclically, and obtaining the degree of superheat within a second preset time period ; Until the superheat degree is greater than or equal to the second threshold at least once within the second preset time period. 8. The temperature control method according to any one of claims 1 to 7, further comprising: Based on the difference between the evaporation temperature and the target value, the flow rate of the refrigerant in the second heat exchange path is adjusted through a PID algorithm. 9. The temperature control method according to any one of claims 1 to 7, characterized in that a pressure sensor is provided at the inlet end of the second compressor. 10. The temperature control method according to any one of claims 1 to 7, wherein the first refrigeration system comprises a multi-stage refrigeration circuit for sequential heat exchange, and the first heat exchange path is connected to one of the Between the condenser and the throttling part of the refrigeration circuit.

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